阅读说明：本技术 具有改善频率区分的超再生收发器 (Super-regenerative transceiver with improved frequency discrimination ) 是由 T·L·奈恩 T·O·洛施洛 于 2018-02-11 设计创作，主要内容包括：本公开提供了一种带有具有可控增益的反馈元件的超再生收发器。超再生收发器利用可控增益来改善RF信号数据灵敏度和改善RF信号数据捕获速率。本文描述的超再生收发器允许在宽范围的频率和一系列通信协议上捕获信号数据。本文描述的超再生收发器是可调谐的,消耗非常少的功率用于操作和维护,并且即使在由非常小的电源(例如,纽扣电池)供电时也允许长期操作。(The present disclosure provides a super-regenerative transceiver with a feedback element having a controllable gain. The super regenerative transceiver utilizes controllable gain to improve RF signal data sensitivity and improve RF signal data capture rate. The super regenerative transceivers described herein allow signal data to be captured over a wide range of frequencies and a range of communication protocols. The super regenerative transceivers described herein are tunable, consume very little power for operation and maintenance, and allow long term operation even when powered by a very small power source (e.g., a coin cell battery).)

1. An RF receiver, comprising:

A resonator comprising two or more electrodes, wherein each of the two or more electrodes is coupled to at least one other of the two or more electrodes, and the two or more electrodes comprise at least one feedback electrode; and

a feedback element coupled to the at least one feedback electrode, wherein the feedback element has a gain that is controlled based at least in part on one or more feedback control signals and that is controlled to change from a first value to a second value through at least one intermediate value during a period of a single symbol.

2. The RF receiver of claim 1 wherein the feedback element comprises a controlled impedance element.

3. the RF receiver of claim 2 wherein the two or more electrodes include at least two feedback electrodes and the controlled impedance element is differentially coupled to the at least two feedback electrodes.

4. The RF receiver of claim 2 wherein at least one of the one or more feedback control signals controls at least one of the at least one feedback electrodes to be coupled to a dissipative element during at least a portion of a period of a single symbol.

5. the RF receiver of claim 1 wherein the two or more electrodes include at least two feedback electrodes, the feedback element includes a closed loop feedback element, and the closed loop feedback element is coupled to the at least two feedback electrodes.

6. The RF receiver of claim 5 wherein the resonator includes four or more electrodes, the four or more electrodes include at least four feedback electrodes, and the closed-loop feedback element is differentially coupled to the at least four feedback electrodes.

7. The RF receiver of claim 5 wherein at least one of the one or more feedback control signals controls at least one of the at least two feedback electrodes to be coupled to a dissipative element during at least a portion of a period of a single symbol.

8. The RF receiver of claim 5 wherein at least one of the one or more feedback control signals controls at least two of the at least two feedback electrodes to be coupled to each other via a dissipative element to each other during at least a portion of a period of a single symbol.

9. The RF receiver of claim 1, further comprising:

A tuning element coupled to at least one tuning electrode, wherein the two or more electrodes include the at least one tuning electrode, the tuning element is controlled by one or more frequency control signals, and a resonant frequency of the resonator is controlled by the tuning element.

10. The RF receiver of claim 9 wherein the tuning element includes one or more capacitors, at least one of the one or more frequency control signals controls an output capacitance of the tuning element, and the resonant frequency is based at least in part on the output capacitance of the tuning element.

11. The RF receiver of claim 9, wherein the tuning element comprises a voltage source, at least one of the one or more frequency control signals controls an output voltage of the tuning element, and the resonant frequency is based at least in part on the output voltage of the tuning element.

12. The RF receiver of claim 9, wherein at least one of the one or more frequency control signals is based at least in part on a temperature associated with a resonator.

13. The RF receiver of claim 9 wherein at least one of the at least one feedback electrode and at least one of the at least one tuning electrode are coupled to a first electrode of the two or more electrodes.

14. The RF receiver of claim 9, further comprising:

a response sensing element coupled to at least one response sensing electrode, wherein the two or more electrodes include the at least one response sensing electrode, an output of the response sensing element is based at least in part on a response of the resonator, and at least one of the frequency control signals is based at least in part on the output of the response sensing element.

15. The RF receiver of claim 14 wherein the response of the resonator is an amplitude of a voltage on at least one of the at least one responsive sense electrode and the resonant frequency is based at least in part on an output of the responsive sense element.

16. The RF receiver of one of claims 1-15, wherein the gain is a loop gain, the first value corresponds to a loop gain of zero or less, the intermediate value corresponds to a loop gain between zero and one, and the second value corresponds to a loop gain of one or more.

17. The RF receiver of one of claims 1-15, wherein the gain is a loop gain and the first value corresponds to a loop gain of zero or less.

18. The RF receiver of one of claims 1-15, wherein the gain is a loop gain, and the intermediate value corresponds to a loop gain of less than one.

19. the RF receiver of one of claims 1-15, wherein at least one of the one or more feedback control signals controls the gain to change to a negative value during at least a portion of a period of a single symbol.

20. The RF receiver of one of claims 1-15, wherein the first value of the gain corresponds to a feedback element having a negative gain.

21. the RF receiver of one of claims 1-15, wherein the intermediate value is controllable and is selectable from two or more target values.

22. The RF receiver of one of claims 1-15, wherein the resonator type comprises at least one of the following MEMS categories: surface micromachined micromechanical structures, bulk micromachined micromechanical structures, piezoelectrically actuatable micromechanical structures, and capacitively actuatable micromechanical structures.

23. The RF receiver of one of claims 1-15, wherein the resonator has a first Q factor with a gain equal to the first value, the resonator has a second Q factor with a gain equal to the intermediate value, and the first Q factor is different from the second Q factor.

24. The RF receiver of one of claims 1-15, further comprising:

A response sensing element coupled to at least one response sensing electrode, wherein the two or more electrodes include the at least one response sensing electrode, and an output of the response sensing element is based at least in part on a response of the resonator.

25. The RF receiver of claim 24 wherein the resonator has a first Q factor with a gain equal to the first value, the resonator has a second Q factor with a gain equal to the intermediate value, and the first Q factor is different from the second Q factor.

26. The RF receiver of claim 24 wherein the response of the resonator is an amplitude of a voltage on at least one of the at least one responsive sense electrodes.

27. The RF receiver of claim 24 wherein the response of the resonator is a magnitude of current sensed using at least one of the at least one responsive sense electrodes.

28. the RF receiver of claim 24 wherein at least one of the one or more feedback control signals is based at least in part on an output responsive to a sensing element.

29. The RF receiver of claim 24 wherein at least one of the first value, the second value, or the intermediate value is based at least in part on an output of the responsive sensing element.

30. a system for capturing symbol data from a wireless signal using an RF receiver, the system comprising:

A resonator comprising two or more electrodes, wherein each of the two or more electrodes is coupled to at least one other of the two or more electrodes, and the two or more electrodes comprise at least one feedback electrode;

A feedback element coupled to the at least one feedback electrode, wherein the feedback element has a gain and the gain is controlled based at least in part on one or more feedback control signals;

One or more processors; and

One or more memories operatively coupled to at least one of the one or more processors and having instructions stored thereon that, when executed by at least one of the one or more processors, cause the system to:

Providing instructions to set a gain to a first value during a first portion of a period of a single symbol, wherein the gain is set based at least in part on at least one feedback control signal of the one or more feedback control signals comprising first data;

Providing instructions to set a gain to an intermediate value during a second portion of a period of a single symbol, wherein the gain is set based at least in part on at least one of the one or more feedback control signals including second data, and the intermediate value is between a first value and a second value; and

providing instructions to set a gain to a second value during a third portion of a period of a single symbol, wherein the gain is set based at least in part on at least one feedback control signal of the one or more feedback control signals comprising third data.

31. The system of claim 30, wherein the gain is a loop gain, the first value corresponds to a loop gain of zero or less, the intermediate value corresponds to a loop gain between zero and one, and the second value corresponds to a loop gain of one or more.

32. a computer-implemented method of capturing symbol data from a wireless signal using an RF receiver, wherein the RF receiver comprises a resonator and a feedback element, the resonator comprises two or more electrodes, each of the two or more electrodes is coupled to at least one other of the two or more electrodes, the two or more electrodes comprise at least one feedback electrode, the feedback element is coupled to the at least one feedback electrode, the feedback element has a gain, and the gain is controlled based at least in part on one or more feedback control signals, the method comprising:

Providing, by at least one of the one or more processors, instructions to set a gain to a first value during a first portion of a period of a single symbol, wherein the gain is set based at least in part on at least one feedback control signal comprising first data in the one or more feedback control signals;

Providing, by at least one of the one or more processors, instructions to set a gain to an intermediate value during a second portion of a period of the single symbol, wherein the gain is set based at least in part on at least one of the one or more feedback control signals including second data, and the intermediate value is between a first value and a second value; and

Providing, by at least one of the one or more processors, instructions to set a gain to a second value during a third portion of a period of the single symbol, wherein the gain is set based at least in part on at least one feedback control signal including third data in the one or more feedback control signals.

33. The method of claim 32, wherein the gain is a loop gain, the first value corresponds to a loop gain of zero or less, the intermediate value corresponds to a loop gain between zero and one, and the second value corresponds to a loop gain of one or more.

34. One or more computer-readable media storing instructions for capturing symbol data from a wireless signal using an RF receiver, wherein the RF receiver comprises a resonator and a feedback element, the resonator comprises two or more electrodes, each of the two or more electrodes is coupled to at least one other of the two or more electrodes, the two or more electrodes comprise at least one feedback electrode, the feedback element is coupled to the at least one feedback electrode, the feedback element has a gain, and the gain is controlled based at least in part on one or more feedback control signals, wherein the instructions, when executed by one or more computing devices, cause at least one of the one or more computing devices to:

Providing instructions to set a gain to a first value during a first portion of a period of a single symbol, wherein the gain is set based at least in part on at least one feedback control signal of the one or more feedback control signals comprising first data;

Providing instructions to set a gain to an intermediate value during a second portion of a period of a single symbol, wherein the gain is set based at least in part on at least one of the one or more feedback control signals including second data, and the intermediate value is between a first value and a second value; and

Providing instructions to set a gain to a second value during a third portion of a period of a single symbol, wherein the gain is set based at least in part on at least one feedback control signal of the one or more feedback control signals comprising third data.

35. The computer-readable medium of claim 34, wherein the gain is a loop gain, the first value corresponds to a loop gain of zero or less, the intermediate value corresponds to a loop gain between zero and one, and the second value corresponds to a loop gain of one or more.

36. An RF receiver, comprising:

Two or more resonators, wherein each of the two or more resonators includes two or more electrodes, wherein each of the two or more electrodes of a resonator is coupled to at least one other of the two or more electrodes of the respective resonator;

A feedback element coupled to at least one port, wherein the feedback element has a gain, the gain is controlled based at least in part on one or more feedback control signals, and the gain is controlled to change from a first value to a second value through at least one intermediate value during a period of a single symbol; and

A switch configured to couple each of the at least one port to at least one of two or more electrodes of an active resonator, wherein the active resonator is selected from the two or more resonators based at least in part on one or more resonator selection signals.

37. The RF receiver of claim 36 wherein a first resonator of the two or more resonators has a first resonant frequency that is tunable over a first resonant frequency range, a second resonator of the two or more resonators has a second resonant frequency that is tunable over a second resonant frequency range, and the first resonant frequency range is different from the second resonant frequency range.

38. A system for capturing symbol data from a wireless signal using an RF receiver, the system comprising:

Two or more resonators, wherein each of the two or more resonators includes two or more electrodes, wherein each of the two or more electrodes of a resonator is coupled to at least one other of the two or more electrodes of the respective resonator;

A feedback element coupled to at least one port, wherein the feedback element has a gain and the gain is controlled based at least in part on one or more feedback control signals;

a switch configured to couple each of the at least one port to at least one of two or more electrodes of an active resonator, wherein the active resonator is selected from the two or more resonators based at least in part on one or more resonator selection signals;

One or more processors; and

One or more memories operatively coupled to at least one of the one or more processors and having instructions stored thereon that, when executed by at least one of the one or more processors, cause the system to:

Providing instructions to select a first resonator of the two or more resonators as the active resonator, wherein the first resonator is selected as the active resonator based at least in part on at least one resonator selection signal of one or more resonator selection signals that includes first data;

Providing instructions to set a gain to a first value during a first portion of a period of a single symbol, wherein the gain is set based at least in part on at least one feedback control signal of the one or more feedback control signals comprising second data;

providing instructions to set a gain to an intermediate value during a second portion of a period of a single symbol, wherein the gain is set based at least in part on at least one of the one or more feedback control signals including third data, and the intermediate value is between a first value and a second value; and

Providing instructions to set a gain to a second value during a third portion of a period of a single symbol, wherein the gain is set based at least in part on at least one feedback control signal of the one or more feedback control signals comprising fourth data.

39. A computer-implemented method of capturing symbol data from a wireless signal using an RF receiver, wherein the RF receiver comprises two or more resonators, each of the two or more resonators comprising two or more electrodes, each of the two or more electrodes of a resonator coupled to at least one other of the two or more electrodes of a respective resonator, a feedback element coupled to at least one port, the feedback element having a gain that is controlled based at least in part on one or more feedback control signals, and a switch configured to couple each of the at least one port to at least one of the two or more electrodes of an active resonator, and the active resonator is selected from the two or more resonators based at least in part on one or more resonator selection signals, the method comprises the following steps:

Providing, by at least one of the one or more processors, instructions to select a first resonator of the two or more resonators as the active resonator, wherein the first resonator is selected as the active resonator based at least in part on at least one resonator selection signal of the one or more resonator selection signals that includes first data;

Providing, by at least one of the one or more processors, instructions to set a gain to a first value during a first portion of a period of a single symbol, wherein the gain is set based at least in part on at least one feedback control signal comprising second data in the one or more feedback control signals;

Providing, by at least one of the one or more processors, instructions to set a gain to an intermediate value during a second portion of a period of the single symbol, wherein the gain is set based at least in part on at least one of the one or more feedback control signals including third data, and the intermediate value is between a first value and a second value; and

providing, by at least one of the one or more processors, instructions to set a gain to a second value during a third portion of a period of the single symbol, wherein the gain is set based at least in part on at least one feedback control signal including fourth data in the one or more feedback control signals.

40. a computer-implemented method of tuning a resonant frequency of an RF receiver, wherein the RF receiver comprises a resonator, a tuning element, a response sensing element, and a frequency source, the resonator comprising two or more electrodes, each of the two or more electrodes coupled to at least one other of the two or more electrodes, the two or more electrodes comprising at least one tuning electrode, the two or more electrodes comprising at least one response sensing electrode, the two or more electrodes comprising at least one drive electrode, the tuning element coupled to the at least one tuning electrode, the tuning element controlled by one or more frequency control signals, the resonant frequency of the resonator controlled by the tuning element, the response sensing element coupled to the at least one response sensing electrode, an output of the response sensing element based at least in part on a response of the resonator, a frequency source is coupled to the at least one drive electrode, the frequency source having a frequency reference signal with a reference frequency, the frequency source having a target resonant frequency signal with a target resonant frequency, and the target resonant frequency being a multiple of the reference frequency, the method comprising:

providing, by at least one of the one or more processors, instructions to control a frequency source to drive the resonator using a target resonant frequency signal;

Providing, by at least one of the one or more processors, instructions to control the tuning element to adjust the resonant frequency of the resonator;

Capturing, by at least one of the one or more processors, an output responsive to the sensing element;

Determining, by at least one processor of the one or more processors, a tuning value based at least in part on the captured output of the responsive sensing element; and

Instructions to control the tuning element to a tuning value are provided by at least one of the one or more processors.

41. A computer-implemented method of tuning a resonant frequency of a resonator, wherein the resonator comprises two or more electrodes, each of the two or more electrodes coupled to at least one other of the two or more electrodes, the two or more electrodes comprising at least one feedback electrode, the two or more electrodes comprising at least one tuning electrode, a feedback element coupled to the at least one feedback electrode, the feedback element having a loop gain controlled based at least in part on one or more feedback control signals, the tuning element coupled to the at least one tuning electrode, the tuning element controlled by one or more frequency control signals, the resonant frequency of the resonator is controlled by a tuning element, a frequency difference detector is coupled to the at least one sensing electrode, and the frequency difference detector has a frequency reference signal with a reference frequency, the method comprising:

Providing, by at least one of the one or more processors, instructions to control a feedback element to set a loop gain to one or more, wherein the resonator generates oscillations at an oscillation frequency based at least in part on the resonant frequency;

Providing, by at least one of the one or more processors, instructions to control the tuning element to adjust the resonant frequency;

Determining, by at least one of the one or more processors and using the frequency difference detector, a relationship between an oscillation frequency signal and the reference frequency signal, wherein the oscillation frequency signal is based at least in part on the oscillation frequency;

Determining, by at least one of the one or more processors, a tuning value based at least in part on the determined relationship; and

Instructions to control the tuning element to a tuning value are provided by at least one of the one or more processors.

42. The RF receiver of claim 4, 7 or 8 wherein the dissipative element comprises a resistive element.

43. An RF receiver, comprising:

A resonator comprising two or more electrodes, wherein each of the two or more electrodes is coupled to at least one other of the two or more electrodes, and the two or more electrodes comprise at least one feedback electrode; and

A feedback element coupled to the at least one feedback electrode, wherein the feedback element has a gain that is controlled based at least in part on one or more feedback control signals and the gain is controlled to change a Q factor of the resonator from a first value to a second value during a period of a single symbol.

Technical Field

The present disclosure relates generally to wireless communication receivers, wireless communication transmitters, and electronic oscillator designs, systems, methods, and devices. In particular, the present disclosure relates to designs, systems, methods, and apparatus for enabling improvements to super regenerative resonator architectures used in wireless receivers, wireless transmitters, and electronic oscillators. More particularly, the present disclosure relates to improvements to super regenerative resonator architectures that allow for low power wireless receivers and transmitters, as well as improvements in the frequency stability and operating frequency range of the oscillator.

Background

the field of RF-MEMS has so far improved many aspects of wireless communication, with tremendous gains in reduced power consumption and reduced size compared to conventional technologies. On-chip MEMS devices now offer applications from compact and low phase noise reference oscillators to band-selective RF front-end duplexers. However, there is still greater potential if the complete radio can be implemented with the high quality factor and CAD definable frequencies possible in MEMS without the need to use power-intensive mixing and broadband analog-to-digital conversion in modern RF architectures.

Since a high Q-factor can be achieved in some resonators, super-regenerative receivers manufactured using such resonators not only provide the Amplitude Shift Keying (ASK) possible in conventional super-regenerative receivers, but also allow differentiation between Frequency Shift Keying (FSK), which is a key capability of modern digital communication systems. The previous patent application PCT/US2015/031251 describes a high Q-factor micro-electromechanical systems (MEMS) based resonator that can be used for this application. Previous patent application PCT/US2015/031589 describes a MEMS-based super regenerative transceiver that provides FSK decoding capability.

disclosure of Invention

The present disclosure describes improvements that allow super-regenerative receivers to operate using many modern protocols using FSK or on-off keying (OOK) modulation, including but not limited to implementations of the bluetooth or GSM standards or Z-Wave. The present disclosure also describes an improved MEMS-based resonator for use in a super-regenerative receiver.

In addition to the protocols listed above, the present disclosure describes improvements in implementations that allow super regenerative receivers to be used for at least one or more of the following protocols: zigbee, IEEE802.15.4, SigFox, Helium, LORA, GPS, ANT +, NB-IoT, and Dash 7.

Bluetooth, Bluetooth Low Energy (BLE), and Z-Wave are protocols widely used for home and business automation and consumer wireless applications. Z-Wave focuses on low data rates of 9.6kbps to 40kbps at 900MHz, providing a radio technology with increased range and simpler RF hardware and standard compatibility compared to 2.4GHz protocols such as Zigbee. In fact, simple frequency shift keying modulation and reasonable specifications allow such transceivers to be implemented for use in home and industrial monitoring applications with little difficulty. The bluetooth and BLE standards provide greater compatibility and more modes of operation for a wide variety of consumer and other commercial applications, but at the cost of increased complexity. While designed for battery-operated remote devices, current implementations of these standards typically consume unfriendly 15mW to 50mW or more of battery, apparently far from long-term operation for the small batteries required to deploy contemplated low-cost sensor particles in a ubiquitous internet of things system in the future.

power consumption remains an important consideration in the design of wireless transceivers. With the increasing number of such transceivers for internet of things (IoT) applications and consumer electronics, the desire for low power operation is highly commercially relevant. By reducing the number of component parts and simplifying the complexity of data communication, power consumption can be reduced. In some embodiments of the present disclosure, a Radio Frequency (RF) resonator is embedded in an active controllable positive feedback loop to form a tunable RF channel selection radio transceiver employing a super regenerative reception scheme. In some embodiments, in a radio employing a super-regenerative reception scheme, an amplifier combined in closed-loop feedback super-regeneratively amplifies an input signal at resonance, allowing for detection of weak radio signals without requiring a complex, power-hungry architecture. In some embodiments, the resulting transceiver utilizes the high Q factor (500-.

in some embodiments, using one or more electrodes of the resonator as a signal input (e.g., from an antenna) with a separate one or more electrodes for super regenerative gain, affects filtering that suppresses input signal feedthrough, allowing for a cleaner filtered output. In some embodiments, differential signals are used to further suppress feedthrough. Super-regenerative receivers that used conventional techniques in the past typically included a two-port device wired back to the amplifier. This means that the input signal has to be connected directly to the input of the amplifier, which results in that anything entering the receiver system (e.g. from the antenna) is amplified without any filtering whatsoever. If there is large interference at frequencies other than the desired frequency (typically for radio applications), then this can cause serious problems and often prevents reception. In some embodiments, these inputs may be isolated from the amplifier using multiple isolation electrodes that may utilize the disclosed resonator design, thereby solving this problem.

The disclosed receiver, transmitter and transceiver are well suited for wireless sensor node applications where low power consumption and reliability are critical. In some embodiments, controllable frequency tuning also allows the same device to operate as a frequency shift keying transmitter or to have a simple output switching, on-off keying transmitter, thus forming a complete transceiver in one very simple device. In some embodiments, the geometric flexibility of the resonator structure design allows for a wide range of available RF frequencies, from 60MHz VHF and lower frequencies up to UHF or higher. For example, a set of resonators, each designed for a particular frequency range, may be coupled through a switching network to one or more receiver antennas, and one or more feedback elements with optional one or more tuning elements, and optional one or more response sensing elements, to create a receiver that may span a wide frequency range.

Embodiments of the present disclosure are directed to devices, systems, and methods for capturing symbol data from a wireless signal using an RF receiver having a resonator and a feedback element with variable gain. Implementations are directed to controlling the frequency response of a resonator using a feedback element gain to improve receiver signal sensitivity or receiver data rate. Additional implementations are directed to tuning resonator resonance frequencies and extending receiver operating frequency ranges using multiple resonators.

Drawings

FIG. 1 illustrates an exemplary schematic diagram of a MEMS-based super-regenerative receiver.

Fig. 2A, 2B, 2C, 2D and 2E illustrate exemplary time series diagrams of incoming wireless FSK signals, feedback element gains, feedback element control signals, resonator responses and captured data.

Fig. 3A, 3B, and 3C show three different time series plots of exemplary feedback element gain and corresponding response of the resonator.

Fig. 4A and 4B show exemplary responses of two resonators with and without frequency response shaping implemented by a feedback element.

FIG. 5 illustrates an exemplary schematic diagram of a MEMS-based super regenerative receiver including a dual resonator for capturing both marker and spatial data.

Fig. 6 illustrates an exemplary schematic diagram of a closed-loop feedback element coupled to a resonator.

FIG. 7 illustrates an exemplary schematic diagram of a control structure for a closed-loop feedback element.

Fig. 8 illustrates an exemplary circuit diagram of a closed loop feedback element.

Fig. 9 illustrates an exemplary schematic diagram of a controlled impedance element coupled to a resonator.

fig. 10 illustrates an exemplary schematic diagram of a control structure for a controlled impedance element.

Fig. 11 illustrates an exemplary circuit diagram of a controlled impedance element.

Fig. 12A and 12B illustrate exemplary schematic diagrams of a super-regenerative receiver including a resonator array and frequency sensitivity of resonators in the resonator array, respectively.

fig. 13 illustrates an exemplary schematic diagram for a composite resonator including two mechanical resonators coupled to each other via a mechanical coupling beam.

Fig. 14 illustrates an exemplary schematic diagram of a reference frequency generator for tuning the resonant frequency of a resonator in a super regenerative receiver.

Fig. 15A, 15B, 15C, and 15D illustrate steps of an exemplary process flow for manufacturing a resonator.

Fig. 16A, 16B, 16C, and 16D illustrate steps of an exemplary process flow for fabricating a resonator.

Fig. 17A and 17B illustrate exemplary schematic diagrams of a closed-loop feedback element coupled to a resonator and a controlled impedance element coupled to the resonator, respectively, each illustrating a differential connection between some of the ports of the two elements.

fig. 18 illustrates an exemplary circuit diagram of a simplified model of an amplifier coupled to a resonator.

fig. 19 illustrates an exemplary circuit diagram of a controlled impedance element using differential connections.

Detailed Description

the present disclosure describes radio receiver, transmitter and transceiver embodiments that include resonators (e.g., MEMS-based resonators) for home and industrial sensor/actuator modules or other wireless communication applications to substantially reduce power consumption to a level that allows continuous operation on coin cells for many years. In some embodiments, the disclosed apparatus employs a super-regenerative radio receiver architecture with resonators (e.g., MEMS-based resonators) in order to provide the simplicity of the architecture necessary for the required power reduction, and to allow sufficient frequency selection in order to achieve FSK-based demodulation and nearby channel rejection required to comply with modern protocol standards.

due to the high Q-factor achievable in MEMS devices, super-regenerative receivers fabricated using such resonators not only provide the amplitude shift keying possible in conventional super-regenerative receivers, but also allow for the differentiation of frequency shift keying, which is a key capability of modern digital communication systems. Indeed, it is this capability that allows MEMS-based radios to operate using bluetooth, BLE, Z-Wave, or other modern protocols.

in some embodiments, with quality factors (Q-factors) of thousands or even GHz frequencies, the resonators described herein (e.g., MEMS-based resonators) readily allow tuning to the closely spaced kHz band ideal for sensor nodes without the need for currently used processing and power-intensive spreading methods. In some embodiments, the power consumption of an oscillator constructed from such a resonator has been demonstrated below 100 μ W, even in the face of moderate resonator impedance in the k Ω range. Such oscillators are ideally suited for targeted wireless sensor node and battery operated wireless relay particle applications where low power consumption and reliability are critical.

An exemplary schematic diagram of a super-regenerative receiver is illustrated in fig. 1. In an exemplary embodiment, super-regenerative receiver 100 includes a resonator 101 (e.g., a piezoelectric transduced lamb wave RF MEMS resonator) having electrodes 102, 103, 104, and 105. Receiver 100 receives a wireless signal (e.g., at 900MHz) having FSK encoded symbol data using antenna 106 coupled to electrode 102. The electrodes 103 and 104 are coupled to a closed-loop feedback element 107 comprising a variable gain amplifier (not shown) to create a feedback loop. The resonance frequency of the resonator 101 may be controlled by a tuning element 108, the tuning element 108 comprising a variable capacitor, coupled to the electrode 105. An output of the closed loop feedback element 107 is coupled to an envelope detector 109. The output of the envelope detector 109 is connected to an amplifier 110. The output of the amplifier 110 is connected to a comparator 111. The output of the comparator 111 is connected to an output flip-flop 112. An output of the output flip-flop 112 provides demodulated symbol data 113 based on the received wireless signal. The output of the amplifier 110 is also connected to an average peak detector 114. The output of the average peak detector 114 is connected to a gain controller 115. A signal 116 from a clock specifying the timing of the symbol data is also connected to the gain controller 115. The gain controller 115 controls the gain of the closed-loop feedback element 107 to capture symbol data in the wireless signal.

In some embodiments, one or more of the envelope detector 109, the amplifier 110, or the average peak detector 114 together form a responsive sensing element. In some embodiments, the gain controller 115 uses the input from the average peak detector 114 to adjust the gain of the closed-loop feedback element 107 to account for the amplitude of the received wireless signal (e.g., depending on the distance between the receiver 100 and the transmitter (not shown), or the transmitter power). As described below, the gain controller 115 adjusts the gain of the closed-loop feedback element 107 one or more times during a period of a single symbol to capture symbol data. In some embodiments, receiver 100 may include a die with resonator 101 electrically connected (e.g., using wire bonding) to one or more dies with the remaining elements. In some embodiments, receiver 100 may include a die with resonator 101 and one or more elements, with the remaining elements on one or more other dies. In some embodiments, one or more of the feedback element, tuning element, or responsive sensing element may comprise a common component. In some embodiments, the additional components (e.g., amplifiers, filters) may be part of a feedback element, tuning element, or response sensing element, which is then in turn coupled to the resonator.

Using an exemplary embodiment of a super regenerative receiver, fig. 2A illustrates an exemplary wireless FSK signal 201 received by the super regenerative receiver. As shown in fig. 2B, a feedback element coupled to a resonator in the super regenerative receiver changes its gain 202, as shown during each period of a single symbol, to capture incoming data on the received wireless FSK signal 201. As shown in fig. 2C, the control signal 203 is used by the feedback element to change the gain within each period of a single symbol (see fig. 8 for a description of CLKS, CLKF, CLKIN, CLKOUT, and CLKCON). As shown in fig. 2D, the super-regenerative receiver identifies an incoming "1" or "0" (the response of the resonator, as shown at 204) at its core by measuring the rate at which the oscillation grows in response to positive feedback from the feedback element. In this embodiment, in case the resonator is tuned to a frequency corresponding to "1", the antenna signal power not received in the resonance pass band results in a slow rise of the oscillation amplitude, which indicates "0". On the other hand, in case power in resonance is received, the signal is coupled to a positive feedback loop, accelerating the rise time to indicate "1". In some embodiments, the output of the super-regenerative receiver shows the received data 205, fig. 2E, based on thresholding of the envelope detector output (the threshold is shown in fig. 2D by dashed line 206). Operating in this manner, such super-regenerative receivers form Binary Frequency Shift Keying (BFSK) demodulators in which the FSK "mark" ("1") and "space" ("0") correspond to the on and off resonant signals, respectively.

in some embodiments, the envelope detector may be a simple diode detector, a root mean square circuit detector, or an active energy detector. In some embodiments, in addition to detecting the output signal of the resonator, a simple diode detector, a root mean square circuit detector, or an active energy detector (e.g., measuring resonator power, energy, oscillation amplitude) may be used in a response sensing element coupled to other components (e.g., feedback element, tuning element) in the super regenerative receiver. In some embodiments, the tuning element may use the output of the response sensing element to adjust the resonant frequency of the resonator. In some embodiments, the tuning element may be incorporated as part of the feedback element. In some embodiments, the feedback element may use the output of the response sensing element to control the gain when coupled to the resonator. In some embodiments, the feedback element uses an indication of the power signal measured by the responsive sensing element to implement a gain control capability to optimize reception. For example, as the distance between the wireless transmitter and the wireless receiver decreases, the received RF power at the wireless receiver increases, and thus the gain of the feedback element may be reduced (to ensure signal detection and measurement). Similarly, if the transmit power of the wireless transmitter increases, the received RF power at the wireless receiver increases, and thus the gain of the feedback element may be reduced.

In some embodiments using high Q factor MEMS based resonators, the super regenerative receiver isolates a single narrow channel while rejecting signals in the nearby spectrum. Isolation is made possible by isolating the input of the feedback element from the input antenna based on passing the signal through the high Q factor MEMS based resonator only through resonance; the frequency response of high Q factor MEMS based resonators prevents off-channel interference. The disclosed embodiments mark a significant improvement over previous super-regenerative receiver architectures where the loop amplifier must handle any spurious signals received by the input antenna without causing excessive intermodulation. In some embodiments using high Q factor MEMS based resonators, filtering any such interference greatly relaxes the linearity of the receiver and thus the power consumption of the receiver.

Sustaining amplifier design

In order for super-regenerative oscillation to occur in any resonator-amplifier system, two conditions must be maintained: 1) the total closed loop phase shift must be zero; and 2) the loop gain must be greater than 1. It is necessary to decide whether we want to use gain or loop gain in the claims. Correlated gain and loop gain may be required. During start-up of the oscillation, the oscillation amplitude is small-initially only constituting noise-and the overall system remains linear. Thus, the oscillator may be modeled using a small signal equivalent circuit, such as the circuit of one possible embodiment presented in fig. 18. One way to understand such oscillators is to use an impedance approach. In this method, the critical conditions for oscillation occur:

Zamp-Zres＝0 (1)

Where Zamp and Zres are the impedances looking into the amplifier 1801 and resonator 1802, respectively. This model is broadly applicable to many embodiments of resonators and amplifiers (as used herein, "feedback element" is used generically to describe an amplifier, including both embodiments of the closed loop feedback element and controlled impedance element described below). This case can also be divided into real and imaginary parts:

-Re[Zamp]＝Re[Zres] (2)

-Im[Zamp]＝Im[Zres] (3)

Here, the real part requires that the effective resistance looking into the amplifier is negative (gain) to compensate for the positive resistance (loss) of the resonator; while the imaginary part sets the phase shift at the oscillation. This simple impedance-based approach provides a general framework that can be used to describe many embodiments of such systems, as long as equivalent impedances can be defined for the resonator and the feedback element.

In one embodiment, a closed loop feedback element in the punch-through (pierce) configuration shown in fig. 8, the first oscillation condition is implemented by a transistor 806, the transistor 806 introducing a 180 ° phase shift between the input 809 and output 808 voltages. At resonance, the phase shift of the lamb wave resonator shown here in one embodiment is 0 °, so an additional 180 ° is required to meet criterion 2. To provide this, the resonator (not shown) must operate in the inductive region, i.e., its frequency is slightly higher than that of the series resonance, and resonates with C1, C2, and C3, which includes the total parasitic capacitance from the resonator, the amplifier, and surrounding structures (e.g., bond pads) at the input 809 and output 808 nodes.

The minimum (or critical) small-signal transconductance gain for onset of oscillation takes the form:

Wherein, C1, 2 ═ C1 ═ C2. When the gain is sufficient to overcome the resonator loss (i.e., loop gain >1), the oscillator loop amplitude rises exponentially with a time constant given by:

where Rx and Lx are equivalent circuit model elements of a resonator tank (tank) (equivalent LRC circuit), and T is loop gain. For the following examples of the perforated and negative-resistance amplifier topology, T ═ Ramp/Rx, where Ramp and Rx are the real parts of Zamp and Zres, respectively. Here Rx is positive and Ramp is negative (indicating the gain of the feedback element). It is noted, however, that this is not the only possible definition of the loop gain, and for other amplifier topologies or models this loop gain may be defined otherwise, as it represents a dimensionless constant equivalent to the overall gain of the resonator + amplifier, regardless of how it may be implemented.

in this disclosure, Ramp and Rx based loop gain defines closed loop feedback element and controlled impedance element embodiments that are applicable in both single ended and differential versions. This provides a general form of loop gain in such systems regardless of the particular amplifier topology (e.g., puncture, transimpedance, negative resistance, etc.) selected. Here, the loop gain for the closed loop feedback element configuration is explicit: gain measured in a closed loop comprising a feedback element and an equivalent resonator circuit model. The above definition of the loop gain is still accurately described for the controlled impedance element configuration, it being understood that the "loop" herein is a combination of the resonator equivalent circuit response, combined with the response of the controlled impedance element. In such a model, the controlled impedance element may be viewed as a transfer function between the voltage at the controlled impedance element node connected to the resonator and the resulting current generated at the controlled impedance element node (or vice versa). For example, for a negative resistance amplifier configuration, if the controlled impedance element node is only grounded, then the circuit produces a larger ac current than if it were affected. In essence, the transfer function "closes" the loop with the resonator response, allowing a loop gain to be defined, and allows increased oscillation in the case where the controlled impedance element is designed such that the loop gain can be greater than 1.

In general, the disclosed feedback element + resonator combination acts as a line-width controllable (where "line-width" refers to the resonator frequency response shape) resonator with a loop gain anywhere between 0 (e.g., the unaltered natural loss of the resonator (e.g., amplifier disconnection)) to just below a loop gain of 1. In some embodiments, a loop gain greater than zero but less than 1 is used during the frequency response shaping segment (e.g., 302, 312, 322 of the super-regenerative cycle in fig. 3) to adjust the frequency response shape of the resonator. When the loop gain increases above 1 (e.g., during the symbol data capture segment), the device no longer operates as a resonator, but rather as a self-sustaining oscillator. The resonator signal then grows with each oscillation cycle until the receiver enters the conditioning section, or until non-linearity in the resonator-feedback element loop causes self-limiting. Here, for loop gain >1, the time required for the signal to rise to the threshold amplitude in the resonance is reduced in two ways: first, the driver is resonantly enhanced to produce an initial amplitude of the resonator that is much greater than background thermal noise, and second, as the oscillation increases, this input signal continues to drive the resonator, resulting in a further increase in amplitude during the start of the oscillation beyond that provided by a response driven purely by the feedback element.

for any filter, the bandwidth of the filter limits the possible data transfer rate. Here, this limit is dictated by the decay time required for the resonator to reach a low dynamic amplitude after receiving the sign on the frequency. If the feedback element adjusts for a segment duration below the decay time of the resonator and omits the frequency response shaping segment, setting the loop gain >1 (e.g., during the symbol data capture segment) will quickly restart oscillation even if there is no on-frequency input signal, e.g., may result in an off-frequency input signal (e.g., "0" bits) being counted as an on-frequency input signal (e.g., "1" bits). In some embodiments, the frequency response shaping method disclosed in fig. 3 not only helps to increase mark-to-space discrimination, but also helps to filter out-of-frequency input signals caused by steeper resonator response roll-off caused by frequency shifts during the frequency response shaping segment, thereby improving signal sensitivity.

After the resonator has received and captured the sign in frequency, setting the amplifier gain equal to zero (e.g., during the tuning segment) results in damping of the resonator oscillation with a time constant equal to the intrinsic damping of the resonator. To further accelerate this decay and prepare the resonator faster for the next capture cycle, resonator oscillation can be damped faster by setting the loop gain below zero (e.g., introducing a dissipative element (e.g., a resistive element) to the resonator + feedback element system). In some embodiments, resonator oscillation decays more quickly during the conditioning segment by shorting one or more resonator electrodes to ground or other DC source (e.g., a positive power supply) through a resistive element. This corresponds to a negative loop gain. In some embodiments, faster damping of resonator oscillations may also be produced using negative feedback by applying an amplified signal that is out of phase with the resonator.

in some embodiments, the super-regenerative receiver varies the gain of the feedback element during each period of a single symbol, see, e.g., fig. 3A-3C. In some embodiments, the feedback element gain varies over three time periods within a single period of a single symbol-the adjustment segment, the frequency response shaping segment, and the symbol data capture segment. As used herein, the names of these segments do not exclude different receiver actions occurring during different segments based on the receiver design (e.g., acquisition during a frequency response shaping segment, frequency response shaping during a conditioning segment). As used herein, an "acquisition period" refers to a period spanning an adjustment period (if not omitted), followed by a frequency response shaping period, followed by a symbol data acquisition period. In some embodiments, during the adjustment segment, the feedback element gain is controlled to reset the resonator, e.g., to damp oscillation of the resonator (e.g., from a previous symbol data capture state). By attenuating the in-resonance oscillations generated by the "1" bit data during the previous period of a single symbol, the adjustment segment may increase the sensitivity of measuring the "0" bit immediately after the 1 bit before measuring the "0" bit data in the current period of a single symbol. In some embodiments, tuning of the resonator may include damping oscillation of the resonator by drawing power from the resonator, for example, by adding a dissipative element (e.g., a resistor, introducing a viscous fluid (e.g., a viscous gas) in the environment of the MEMS-based resonator) to the resonator. In some embodiments, tuning of the resonator may include decoupling the feedback element from the resonator (described herein as setting the gain of the feedback element to zero and allowing the resonator to decay at its natural rate). In some embodiments, tuning of the resonator may include grounding one or more electrodes to which the feedback element is connected through a resistive element (described herein as setting the gain of the feedback element to a negative value). In some embodiments, tuning of the resonator may include connecting together two or more electrodes to which the feedback element is connected via a resistive element (described herein as setting the gain of the feedback element to a negative value).

In some embodiments, the feedback element gain is fixed during the adjustment segment. In some embodiments, the feedback element gain varies during the adjustment segment. The shorter duration of the conditioning segment allows more time to capture the input signal, thereby increasing sensitivity or data rate. In some embodiments, the adjustment segment may be shorter (e.g., adjustment segment time < about 1%, 5%, 10%, 25%, or 50% of the period of a single symbol) as compared to the period of a single symbol. In some embodiments, the conditioning segment may be shorter (e.g., conditioning segment time < about 1%, 5%, 10%, 25%, or 50% of the capture period) as compared to the capture period. In some embodiments, the conditioning segment may be eliminated.

In some embodiments, during the frequency response shaping segment, the feedback element gain is controlled to improve the frequency response of the resonator, e.g., increase the frequency sensitivity of the resonator, increase the Q factor of the resonator. In some embodiments, the frequency response of the resonator is improved by increasing the feedback element gain (e.g., relative to the feedback element gain during the adjustment segment) during the frequency response shaping segment. In some embodiments, the frequency response of the resonator is improved by increasing the feedback element gain in a single step during the frequency response shaping segment-see, e.g., fig. 3A. In some embodiments, the frequency response of the resonator is improved by increasing the feedback element gain in a stepwise manner in two or more steps during the frequency response shaping segment-see, e.g., fig. 3B. In some embodiments, the frequency response of the resonator is improved by continuously increasing the feedback element gain during the frequency response shaping segment-see, e.g., fig. 3C. In some embodiments, the frequency response of the resonator is improved by increasing the feedback element gain and then continuously increasing the feedback element gain in a stepwise manner during the frequency response shaping segment, or vice versa (i.e., continuously increasing and then gradually increasing). In some embodiments, the frequency response shaping segment may be longer than the period of a single symbol (e.g., frequency response shaping segment time > about 1%, 5%, 10%, 25%, or 50% of the period of a single symbol). In some embodiments, the frequency response shaping segment may be longer compared to the acquisition period (e.g., frequency response shaping segment time > about 1%, 5%, 10%, 25%, or 50% of the acquisition period).

In some embodiments, during the symbol data capture segment, the feedback element gain is configured such that the resonator amplitude rises exponentially independent of the oscillation frequency (e.g., loop gain > 1). In some embodiments, the feedback element gain is controlled to produce a loop gain equal to or greater than 1 during the symbol data capture segment. In some embodiments, the resonator output amplitude begins to rise exponentially such that the value of the feedback element gain is equal to or greater than a critical gain value, and the feedback element gain is controlled to be equal to or greater than the critical gain value during the symbol data capture segment. In some embodiments, the feedback element gain is fixed during the symbol data capture segment. In some embodiments, the feedback element gain varies during the symbol data capture segment. In some embodiments, the symbol data capture segment may be longer than the period of a single symbol (e.g., symbol data capture segment time > about 1%, 5%, 10%, 25%, 50%, 75%, or 90% of the period of a single symbol). In some embodiments, the symbol data capture segment may be longer than the capture period (e.g., symbol data capture segment time > approximately 1%, 5%, 10%, 25%, 50%, 75%, or 90% of the capture period).

Fig. 4A illustrates an exemplary frequency response 403 of resonator 401 set to the "1" marker frequency, and an exemplary frequency response 404 of resonator 402 set to the "0" spatial frequency. In this configuration, an incoming wireless FSK signal corresponding to a "0" will cause the resonator 401 to respond due to the wide frequency response 403 of the resonator 401. Similarly, an incoming wireless FSK signal corresponding to a "1" will cause the resonator 402 to respond due to the wide frequency response 404 of the resonator 402. If the frequency response shaping segment is omitted (frequency response 403 or 404 is unmodified) and the feedback element gain is set to a gain corresponding to the symbol data capture segment, then the resulting response of either resonator 401 or 402 will result in an increased likelihood of an error in which either the "0" incoming bit is erroneously identified by resonator 401 as a "1" or the "1" incoming bit is erroneously identified by resonator 402 as a "0".

fig. 4B illustrates an exemplary frequency response 407 of resonator 405 set to the "1" marker frequency, and an exemplary frequency response 408 of resonator 406 set to the "0" spatial frequency. In this configuration, an incoming wireless FSK signal corresponding to a "0" will result in a reduced response of the resonator 405 (compared to the resonator 401 in the configuration in fig. 4A) due to the narrow frequency response 407 of the resonator 405. Similarly, an incoming wireless FSK signal corresponding to a "1" will result in a reduced response of the resonator 406 (compared to the resonator 402 in the configuration in fig. 4A) due to the narrow frequency response 408 of the resonator 406. Where a frequency response shaping segment is included during the capture of the symbol data, the frequency response of the resonator narrows (e.g., from 403 to 407, from 404 to 408), and the increased attenuation of the resonator response caused by the out-of-frequency input during the frequency response shaping segment results in better discrimination between the incoming bits during the symbol data capture segment. In some embodiments, the Q factor of the resonator may vary from a typical value of about 1000 during the tuning section to a typical value of about 20000 during the frequency response shaping section. In some embodiments, the Q factor of the resonator may vary from a typical value of about 10 during the tuning section to a typical value of about 1000 during the frequency response shaping section. In some embodiments, the Q factor of the resonator may vary from a typical value of about 100000 during the adjustment segment to a typical value of about 1000000 during the frequency response shaping segment.

fig. 3A shows the gain of a feedback element coupled to a super-regenerative receiver (304, solid black line) and the response of a resonator in the super-regenerative receiver (305, solid gray line) as a function of time over two cycles of incoming single symbol data in one exemplary embodiment. In fig. 3A, the gain 304 of the feedback element is fixed during each of the adjustment segment 301, the frequency response shaping segment 302, and the symbol data acquisition segment 303. The gain 304 of the feedback element is controlled to change from a first value during the adjustment segment 301 to an intermediate second value during the frequency response shaping segment 302 and to a third value during the symbol data capture segment 303. In some embodiments, the critical value of the gain (306, dashed gray line) may identify the gain above which the resonator exhibits super-regenerative oscillation. In some embodiments, the second value of the gain (during the frequency response shaping segment) may be arbitrarily close to the critical value of the gain 306. In some embodiments, the second value of the gain (during the frequency response shaping segment) may be below the critical value of gain 306 based on the stability of the gain control in order to keep the loop gain below 1.

Fig. 3B shows the gain of a feedback element coupled to the super-regenerative receiver (314, solid black line) and the response of a resonator in the super-regenerative receiver (315, solid gray line) as a function of time over two cycles of incoming single symbol data in one exemplary embodiment. In fig. 3B, the gain of the feedback element is fixed during each of the adjustment segment 311 and the symbol data capture segment 313. During the frequency response shaping segment 312, the gain 314 of the feedback element is varied between two fixed values. The gain of the feedback element is controlled to change from a first value during the adjustment segment 311 to an intermediate second value during the first portion of the frequency response shaping segment 312, to an intermediate third value during the second portion of the frequency response shaping segment 312, and to a fourth value during the symbol data capture segment 313. In some embodiments, the critical value of the gain (316, dashed gray line) may identify the gain above which the resonator exhibits super-regenerative oscillation.

Fig. 3C shows the gain of the feedback element coupled to the super-regenerative receiver (324, solid black line) and the response of the resonator in the super-regenerative receiver (325, solid grey line) as a function of time over two cycles of incoming single symbol data in one exemplary embodiment. In fig. 3C, the gain of the feedback element is fixed during each of the adjustment segment 321 and the symbol data capture segment 323. The gain 324 of the feedback element is continuously varied during the frequency response shaping segment 322. The gain of the feedback element is controlled to change from a first value during the adjustment segment 321, ramp from a first value to a second value during the frequency response shaping segment 322, and change to a second value during the symbol data capture segment 323. In some embodiments, the critical value of the gain (326, dashed gray line) may identify the gain above which the resonator exhibits super-regenerative oscillation.

in some embodiments, the controller may configure the feedback element to capture symbol data multiple times (e.g., more than one capture period) within a period of a single symbol. The traces in fig. 2 and 3 show an exemplary embodiment in which the controller configures the feedback element to capture symbol data once per cycle of a single symbol (one capture cycle). In some embodiments, the controller may configure the feedback element to capture symbol data two or more times (two or more capture periods) per period of a single symbol. For example, if the controller configures the feedback element to capture symbol data twice per period of a single symbol, the feedback element may provide feedback to the resonator over the first adjustment segment, the first frequency response shaping segment, and the first symbol data capture segment over a first portion of the period of the single symbol. The feedback element may provide feedback to the resonator over a remaining portion of the period of the single symbol over a second adjustment segment, a second frequency response shaping segment, and a second symbol data capture segment. In some embodiments, the duration of each acquisition period may be the same during the period of a single symbol. In some embodiments, the duration of at least one acquisition period may be different from at least one other acquisition period during the period of a single symbol. In some embodiments, the feedback during each acquisition period may be the same for each acquisition period during the period of a single symbol. In some embodiments, the feedback during at least one acquisition period (e.g., a single step in gain; see, e.g., the gain waveform in fig. 3A) may be different from at least one other acquisition period (e.g., a ramp in gain; see, e.g., the gain waveform in fig. 3C) during a period of a single symbol. In some embodiments, the duration of the capture period or the duration of one or more segments defining the capture period (e.g., conditioning segment, frequency response shaping segment) may be determined based at least in part on the output of the responsive sensing element. For example, the duration of the symbol data capture period may be based at least in part on the output of the responsive sensing element (e.g., envelope detector), e.g., ending the symbol data capture segment when the resonator oscillation amplitude exceeds a particular threshold. In some embodiments, captured symbol data from each of the capture periods in a single symbol period may be analyzed to determine a detected symbol value. For example, the median of all captured symbol data from a period of a single symbol may be used as the detected symbol value for that particular period of a single symbol.

In some embodiments, as shown in fig. 5, FSK signals may be decoded by a receiver 500, the receiver 500 comprising two mirrored super-regenerative receivers, with one resonator 501 tuned to detect frequency signals in resonance for bit "0" ("space") and the other resonator 551 tuned to detect frequency signals in resonance for bit "1" ("marker"). The resonator 501 includes electrodes 502, 503, 504, and 505. The resonator 551 includes electrodes 552, 553, 554, and 555. The receiver 500 receives a wireless signal (e.g., at 900MHz) with FSK encoded symbol data using an antenna 506 coupled to electrode 502 of resonator 501 and to electrode 555 of resonator 551. Electrodes 503 and 504 of resonator 501 are coupled to a closed-loop feedback element 507 comprising a variable gain amplifier (not shown) to create a feedback loop. Electrodes 553 and 554 of resonator 551 are coupled to a closed-loop feedback element 557 comprising a variable gain amplifier (not shown) to create a feedback loop. The resonance frequency of the resonator 501 may be controlled by a tuning element 508, the tuning element 508 comprising a variable capacitor, coupled to the electrode 505. The resonant frequency of the resonator 551 may be controlled by a tuning element 558, the tuning element 558 comprising a variable capacitor coupled to the electrode 552. The output of the closed loop feedback element 507 is coupled to an envelope detector 509. The output of the closed-loop feedback element 557 is coupled to an envelope detector 559. The output of the envelope detector 509 is connected to an amplifier 510. The output of the envelope detector 559 is connected to an amplifier 560. The output of the amplifier 510 is connected to a first terminal of a comparator 511. An output of amplifier 560 is connected to a second terminal of comparator 511. By comparing the signals from the tag receiver and the spatial receiver, the overall sensitivity is improved and a degree of common mode noise rejection is increased. The output of the comparator 511 is connected to an output flip-flop 512. An output of the output flip-flop 512 provides demodulated symbol data 513 based on the received wireless signal. The output of amplifier 510 and the output of amplifier 560 are also connected to an average peak detector 514. The output of the average peak detector 514 is connected to a gain controller 515. A signal 516 from a clock specifying the timing of the symbol data is also connected to the gain controller 515. The gain controller 515 controls the gain of the closed loop feedback element 507 to capture symbol data in the data signal. Gain controller 515 also controls the gain of closed-loop feedback element 557 to capture symbol data in the data signal.

In some embodiments, to meet the requirements of high Q-factor and narrow bandwidth requirements (e.g., 40kHz for Z-Wave FSK demodulation), a piezoelectric transduction based lamb Wave MEMS resonator may be used. In some embodiments, the MEMS fabrication process used to fabricate such MEMS devices allows for flexibility in fabricating multiple MEMS devices for different frequencies on the same die by changing the CAD design (and thus the post-fabrication geometry) of the MEMS devices. In some embodiments, the fabrication process for fabricating the MEMS device allows CMOS devices to be fabricated on the same die. In some embodiments, a MEMS device includes a 2um thick AIN plate supported by two beams (beams) at a node, where one or more electrodes (e.g., to be used as inputs or outputs of a resonator) are coupled on the AIN plate. To drive the MEMS-based resonator to dynamics, an AC drive voltage is applied to the input electrode to create a strain on the MEMS structure that excites the lamb wave mode shape at resonance. The resonant frequency is given by:

Where Wf is the spacing between any two fingers in all electrodes. E and ρ are the young's modulus and density of the AIN resonator plate (see, e.g., fig. 1, 15, and 16). Here a MEMS-based resonator can be modeled as a series capacitor, inductor and resistor, where resonator mass, stiffness and loss are equivalent to capacitance, inductance and resistance. MEMS-based resonator electrodes provide coupling in this model via transformers, each electrode forming a transformer separate from the equivalent tank circuit. This can be further simplified to an equivalent simple LRC circuit (without transformer) with effective resonators Lx, Rx, Cx and resonant frequency:

It can be appreciated in this electrical model that for such resonators, the resonance frequency can be tuned via an additional shunt capacitance applied to the tuning electrode of the resonator. In effect, this changes the effective capacitance of the resonator tank as in equation 2, thereby changing the resonant frequency. The frequency shift Δ f is controlled by:

Where Cx is the dynamic capacitance of the resonator seen by the tuning electrode and Ctot is the total capacitance at the tuning electrode. It can also be appreciated that this is not the only way to tune the resonant frequency of a MEMS-based resonator. The introduction of variable inductance via, for example, an active inductor circuit can also affect tuning, as can finer tuning methods via temperature or stress control or mechanical effects provided by adding a voltage bias (e.g., a DC voltage) to elements of the MEMS resonator. In some embodiments, the resonant frequency of the resonator may be tuned by at least one or more of: changing the capacitance of a capacitor coupled to the resonator, changing the inductance of an inductor coupled to the resonator, changing the mechanical stress in the resonator element (e.g., using temperature), or changing the mechanical geometry of the resonator (e.g., using a DC voltage bias added to one or more resonator elements).

TABLE 3

Table 3 summarizes an exemplary resonator design where the calculated required power consumption of the amplifier is only 70 μ W.

in some embodiments, the difference in temperature coefficients of different portions of the resonator and between different portions of the resonator may cause the resonant frequency of the resonator to change as the resonator temperature changes. For example, since uncompensated aluminum nitride resonators show a typical Temperature Coefficient (TCF) of-20 to-30 ppm/deg.C, some form of compensation may be required to meet the 27ppm specification required by the Z-Wave specification when operating over the entire commercial temperature range of 0 deg.C to 85 deg.C. In some embodiments, an on-chip temperature measurement element in combination with a tuning element may be used to tune the resonant frequency of the resonator to match the in-resonance frequency of the communication channel.

To achieve sufficient tuning to compensate for the entire commercial range, 2550ppm (assuming-30 ppm/deg.C TCF over 85 deg.C) tuning is required. This requires two separate resonators whose frequencies are 1350ppm apart (assuming some overlap of the operating frequency ranges of the two separate resonators). In some embodiments, referring to table 3, for frequency tuning less than 1350ppm, tuning is affected by a 2pF variable capacitance applied to the tuning electrode of the MEMS resonator(s). A 2pF variable capacitor combines a digitally controlled capacitor bank with a 5fF unit capacitance and a 5fF diode-based varactor. Conveniently, in some embodiments, this same capacitance tuning network allows the desired FSK modulation for transmit operation.

As disclosed herein, the feedback elements used to implement a super-regenerative receiver may be configured in any number of ways. In some embodiments, the feedback element comprises a closed loop feedback element having a controllable gain connected to two or more electrodes of the resonator. In some embodiments, the feedback element comprises a 1-port controlled impedance element connected to one or more electrodes of the resonator. In some embodiments, the controlled impedance element comprises a circuit element that exhibits an effectively varying or fixed impedance at one of its ports. In some embodiments, the controlled impedance element may comprise a negative resistance amplifier. In some embodiments, the feedback element may be controlled to provide a negative gain in order to damp oscillations of the resonator-e.g. during the adjustment segment. In some embodiments, the feedback element may have a controllable gain to produce a change in the frequency response of the resonator-e.g., during a frequency response shaping segment. In some embodiments, the feedback element may be a circuit element that generates a frequency-dependent complex impedance. In some embodiments, the feedback element may be a circuit element that produces a variable gain (e.g., positive and negative, with different amplitudes) or a variable phase shift.

fig. 6 illustrates an exemplary schematic diagram of a closed loop feedback element 601 coupled to two ports of a resonator 602. In some embodiments, the input port 603 of the resonator is coupled to a signal from an antenna (not shown). In some embodiments, the port 604 of the resonator 602 is coupled to a tuning element (not shown). In some embodiments, the tuning element may include a variable capacitance to adjust the resonant frequency of the resonator 602. In some embodiments, the tuning element may apply a voltage bias (e.g., a DC voltage) to one or more elements of the resonator 602 to adjust the resonant frequency of the resonator 602. In some embodiments, port 605 of resonator 602 is coupled to an input of a responsive sensing element (not shown). In some embodiments, the output of the response sensing element is coupled to the input 606 of the closed-loop feedback element 601. In some embodiments, the closed-loop feedback element 601 may use the input from the response sensing element to adjust the gain of the feedback loop (e.g., to account for the amplitude of the input signal from the antenna (e.g., based on the proximity of the wireless signal transmitter)). The closed loop feedback element 601 ports (608, 609) are each connected to one or more electrodes of the resonator 602. In some embodiments, the input 610 of the closed loop feedback element 601 is connected to one or more clock signals. Based on instructions from the controller, one or more clock signals may control the gain of the closed-loop feedback element 601 during a period of a single symbol to generate a signal (e.g., from the resonator 602 (e.g., via port 608)) that is processed by other components as described herein (e.g., envelope detector, comparator, output flip-flop).

fig. 7 illustrates an exemplary schematic diagram of a closed-loop feedback element 701 having a feedback output port 708 and a feedback input port 709 coupled to a resonator (not shown). In some embodiments, the closed loop feedback element 701 includes a control block 711. In some embodiments, control block 711 includes an input 710 that receives one or more clock signals. In some embodiments, control block 711 includes an input 706 that receives an output of a responsive sense element (not shown). The output 712 of the control unit is provided to a closed loop feedback element 701 to adjust the gain between two ports (708, 709) of the feedback element 701.

Fig. 8 illustrates an exemplary circuit diagram for an implementation of a closed loop feedback element having an output 808 and an input 809. The gain of the exemplary feedback element is controlled by the current from the N transistors 801F _1 to 801F _ N and the M transistors 802S _1 to 802S _ M. The voltage signals VF 1-VFN are connected to transistors 801F _ 1-801F _ N in the control unit to regulate the current (and thus the feedback element gain) during the frequency response shaping segment. The clock signal CLKF controls the timing of the frequency response shaping segment. The voltage signals Vs 1-VSM are connected to the transistors 802S _ 1-802S _ M in the control unit to adjust the current (and thus the feedback element gain) during the symbol data capture segment. The clock signal CLKS controls the timing of the symbol data capture segment. Based at least in part on the output of the response sensing element, the ResSen signal is used to determine the gain during the acquisition period based on the resonator response (e.g., based on wireless signal strength), including the gain during the frequency response shaping segment (e.g., controlling the number of transistors 801F _1 through 801F _ N that are turned on) and the gain during the symbol data acquisition segment (e.g., controlling the number of transistors 802S _1 through 802S _ M that are turned on). The clock signal CLKIN controls the transistor 803 to allow the controller to ground the input 809 of the feedback element (through the resistive element) (and also to ground the corresponding electrode or electrodes on the resonator through the resistive element, and thus achieve increased damping of the resonator oscillation). The clock signal CLKOUT controls the transistor 804 to allow the controller to ground the output 808 of the feedback element (through the resistive element) (and also to ground the corresponding electrode or electrodes on the resonator through the resistive element, and thus achieve increased damping of the resonator oscillation). The clock signal CLKCON controls the transistor 805 to allow the controller to connect together the input 809 and output 808 of the feedback element (via a resistive element; also connecting together the corresponding electrode or electrodes on the resonator via a resistive element and thus achieving increased damping of the resonator oscillation). In some embodiments, one or more of transistors 803, 804, and 805 may be enabled during the adjustment segment to attenuate oscillations in the resonator. In some embodiments, one or more of transistors 803, 804, and 805 may include a resistance designed to act as a resistive element (e.g., 1 kiloohm, MOSFET-based channel) that attenuates the resonator. Transistor 806 is an amplifier in the circuit. The transistor 807 is a bias transistor for biasing the output terminal 808 and the input terminal 809 at the same voltage.

Fig. 9 illustrates an exemplary schematic diagram of a feedback element including a 1-port controlled impedance element 901 having a port 909 coupled to a resonator 902. In some embodiments, the input port 903 of the resonator 902 is coupled to a signal from an antenna (not shown). In some embodiments, port 904 of resonator 902 is coupled to a tuning element (not shown). In some embodiments, the tuning element may include a variable capacitance to adjust the resonant frequency of the resonator 902. In some embodiments, the tuning element may apply a voltage bias (e.g., a DC voltage) to one or more elements of the resonator 902 to adjust the resonant frequency of the resonator 902. In some embodiments, port 905 of resonator 902 is coupled to an input of a responsive sensing element (not shown). In some embodiments, the output of the response sensing element is coupled to the input 906 of the controlled impedance element 901. In some embodiments, the controlled impedance element 901 may use the input 906 from the responsive sensing element to adjust the feedback gain by adjusting its impedance (e.g., to account for the amplitude of the input signal from the antenna (e.g., based on proximity of the wireless signal transmitter)). In some embodiments, the input 910 of the controlled impedance element 901 is connected to one or more clock signals. Based on instructions from the controller, one or more clock signals may control the feedback gain of the controlled impedance element 901 during the period of a single symbol to generate a signal (e.g., from the resonator 902 (e.g., via port 909)) that is processed by other components as described herein (e.g., envelope detector, comparator, output flip-flop).

Fig. 10 illustrates an exemplary schematic diagram of a 1-port controlled impedance element 1001 having a feedback port 1008 coupled to a resonator (not shown). In some embodiments, controlled impedance element 1001 includes a control block 1011. In some embodiments, control block 1011 includes an input 1110 that receives one or more clock signals. In some embodiments, control block 1011 includes an input 1006 that receives an output of a responsive sense element (not shown). The output 1012 of the control unit is provided to the controlled impedance element 1001 to adjust the gain of the controlled impedance element 1001.

Fig. 11 illustrates an exemplary circuit diagram for an implementation of a 1-port controlled impedance element having an input 1109 coupled to a resonator (not shown) and an output 1108 coupled to a detector (not shown). In some embodiments, the input 1109 and the output 1108 may be the same node in a controlled impedance element. The gain of the exemplary controlled impedance element is controlled by the current from the N transistors 1101F _1 to 1101F _ N and the M transistors 1102S _1 to 1102S _ M. The voltage signals VF 1-VFN are connected to transistors 1101F _ 1-1101F _ N in the control unit to regulate the current (and thus the feedback gain) during the frequency response shaping segment. The clock signal CLKF controls the timing of the frequency response shaping segment. The voltage signals VS 1-VSM are connected to transistors 1102S _ 1-1102S _ M in the control unit to adjust the currents (and thus the feedback gains) during the symbol data capture segment. The clock signal CLKS controls the timing of the symbol data capture segment. Based at least in part on the output of the response sensing element, the ResSen signal is used to determine the gain during the capture period based on the resonator response, including the gain during the frequency response shaping segment (e.g., controlling the number of transistors 1101F _1 to 1101F _ N that are turned on) and the gain during the symbol data capture segment (e.g., controlling the number of transistors 1102S _1 to 1102S _ M that are turned on). The clock signal CLKIN controls the transistor 1103 to allow the controller to ground the input terminal 1109 of the controlled impedance element (through the resistive element) (also grounding the corresponding electrode on the resonator through the resistive element and thus achieving increased damping of the resonator oscillation). The voltage Vbias controls transistor 1105 to appropriately bias the circuit for operation. In some embodiments, one or more of the transistors 1103 and 1105 may be enabled during the adjustment segment to attenuate oscillations in the resonator. Transistor 1106 is an amplifier in the circuit.

Fig. 19 illustrates an exemplary circuit diagram of an implementation of a 1-port controlled impedance element using a differential connection having a high input 1909 (coupled to a resonator (not shown) input high and a detector (not shown) input high) and a low input 1908 (coupled to a resonator input low and a detector input low). The gain of the exemplary controlled impedance element is controlled by the current from the N transistors 1901F _1 to 1901F _ N and the M transistors 1902S _1 to 1902S _ M. The voltage signals VF 1-VFN are connected to transistors 1901F _ 1-1901F _ N in the control unit to regulate the current (and thus the feedback gain) during the frequency response shaping segment. The clock signal CLKF controls the timing of the frequency response shaping segment. The voltage signals VS 1-VSM are connected to the transistors 1902S _ 1-1902S _ M in the control unit to adjust the currents (and thus the feedback gains) during the symbol data capture segment. The clock signal CLKS controls the timing of the symbol data capture segment. Based at least in part on the output of the response sensing element, the ResSen signal is used to determine the gain during the capture period based on the resonator response, including the gain during the frequency response shaping segment (e.g., controlling the number of transistors 1901F _1 to 1901F _ N that are turned on) and the gain during the symbol data capture segment (e.g., controlling the number of transistors 1902S _1 to 1902S _ M that are turned on). Clock signal CLKIN controls regulating transistors 1905 and 1906 to allow the controller to short (through resistive elements) the inputs 1108 and 1109 of the controlled impedance element. In some embodiments, 1905 and 1906 may be enabled during the conditioning segment to damp oscillations in the resonator. Transistors 1903, 1904, 1907, and 1908 are gain transistors in the circuit.

As shown in fig. 12A, a super regenerative receiver comprising an array of N resonators 1201_1 to 1201_ N connected to a feedback element 1207 using a switching network may provide support over a wide frequency band or may provide the ability to communicate with other FSK based protocols. Each resonator in the array may be tuned to operate at a resonant frequency within a given frequency range using a tuning element. In some embodiments, the resonant frequency of a given resonator may be tuned using a variable capacitor coupled to one or more electrodes of the resonator. In some embodiments, the frequency ranges of the resonators in the array form overlapping or non-overlapping frequency continuum (the non-overlapping continuum shown in fig. 12B) supported by the super regenerative receiver. In some embodiments, the frequency ranges of the resonators in the array may form two or more disjoint frequency continuum supported by the super regenerative receiver (e.g., one group of resonators in the array supports 900-910MHz and the remaining resonators in the array support 950-970 MHz). In some embodiments, the resonator array may be coupled to one or more feedback elements in a differential mode configuration via a switch.

In some embodiments, signals between the resonator and one or more elements in the receiver may be differentially coupled to improve performance. Fig. 17A illustrates an exemplary schematic diagram of a closed-loop feedback element 1701 coupled to two ports of a resonator 1702. In some embodiments, the differential input port 1703 of the resonator is coupled to a signal from an antenna (not shown). In some embodiments, the differential port 1704 of the resonator 1702 is coupled to a tuning element (not shown). In some embodiments, differential port 1705 of resonator 1702 is coupled to an input of a responsive sensing element (not shown). In some embodiments, the output of the response sensing element is coupled to the input 1706 of the closed-loop feedback element 1701. The closed-loop feedback element 1701 differential ports (1708, 1709) are each connected to two or more electrodes of the resonator 1702. In some embodiments, the input 1710 of the closed-loop feedback element 1701 is connected to one or more clock signals. Based on instructions from the controller, one or more clock signals may control the gain of the closed-loop feedback element 1701 during a period of a single symbol to generate a signal (e.g., from the resonator 1702 (e.g., via the differential port 1708)) that is processed by other components as described herein (e.g., envelope detector, comparator, output flip-flop). In some embodiments, one or more of the ports (e.g., 1706, 1710) may be differential ports. In some embodiments, one or more of the differential ports (e.g., 1704, 1708) may be non-differential ports.

Fig. 17B illustrates an exemplary schematic diagram of a feedback element of a 1-port controlled impedance element 1751 including a differential port 1759 coupled to a resonator 1752. In some embodiments, the differential input port 1753 of the resonator 1752 is coupled to a signal from an antenna (not shown). In some embodiments, a differential port 1754 of resonator 1752 is coupled to a tuning element (not shown). In some embodiments, the differential port 1755 of the resonator 1752 is coupled to an input of a responsive sense element (not shown). In some embodiments, the output of the response sensing element is coupled to an input 1756 of a controlled impedance element 1751. In some embodiments, input 1760 of controlled impedance element 1751 is connected to one or more clock signals. Based on instructions from the controller, one or more clock signals may control the feedback gain of the controlled impedance element 1751 during a period of a single symbol to generate a signal (e.g., from the resonator 1752 (e.g., via the differential port 1759)) that is processed by other components as described herein (e.g., envelope detectors, comparators, output flip-flops). In some embodiments, one or more of the ports (e.g., 1756, 1760) may be differential ports. In some embodiments, one or more of the differential ports (e.g., 1754, 1759) may be non-differential ports.

in some embodiments, N sets of resonators and feedback elements may be combined to allow discrimination of N-FSK signals. For example, a 4-FSK signal may be detected with 4 separate resonators + feedback elements, where the resonant frequency of each resonator is set to a different frequency corresponding to the different frequency of the 4-FSK modulation.

In some embodiments, the mechanically coupled resonator array allows further reduction in Rx without significantly reducing the Q factor. Several (N) identical individual resonators may be coupled during fabrication with a mechanically coupled beam that is sized to be half (or a multiple thereof; e.g., 1/2, 1, 11/2, etc.) the wavelength of sound in any displacement mode used for coupling. This forces the individual resonators to move in phase with each other at a single resonant frequency. Effectively, an array of resonators mechanically coupled in this manner behaves as one single resonator with a similar Q factor, but with the addition of a coupling or electrode for each added individual resonator. Fig. 13 shows an exemplary resonator comprising two resonators 1301A and 1301B mechanically coupled via a coupling beam 1301C. The exemplary resonator includes ports 1302, 1303, 1304, and 1305.

Similarly, a widened passband filter may be produced by coupling of multiple resonators (or resonator arrays) using electrically coupled or quarter wave mechanically coupled beams (or odd multiples thereof; e.g., 1/4, 3/4, 5/4, etc.) such that the resonators are dynamically out of phase. Such filters may also be used in the systems disclosed herein to allow for a larger receive bandwidth, a flatter passband, or a faster off-channel frequency filter roll-off than a single resonator provides.

In some embodiments, the ports of the resonator may be connected to two or more of: a port for a feedback element, a port for a tuning element, and a port for a responsive sensing element. In some embodiments, the response sensing element may sense the response (e.g., amplitude, energy, power) of the incoming signal from the antenna. In some embodiments, the output of the response sensing element may be based at least in part on the response (e.g., amplitude, energy, power) of the incoming signal from the antenna. In some embodiments, the response sensing element may provide an output to the feedback element or the tuning element based at least in part on an incoming signal from the antenna. In some embodiments, the response sensing element may be coupled to the same port as that used for the RF input (e.g., from an antenna).

In the illustration and description, the responsive sensing element (e.g., detector) can be implemented in a variety of ways. When drawn using diode notation (simple detector), the detector can be fabricated using any one or any combination of the following: envelope detectors, voltage peak detectors, Vrms detectors, diode detectors, power (or energy) detectors, voltage square detectors, notch filters, nonlinear notch filters, and even counter-based systems (counting the period or difference in frequency between signals on or off frequency).

In some embodiments, the resonant frequency of the resonator may be different from the target frequency (e.g., the marker frequency) due to one or more of the following factors: device manufacturing variations (e.g., due to variations in film deposition thickness, etch undercutting, photolithography), changes in resonator temperature (e.g., due to changes in ambient temperature), and changes in the mechanical properties of the resonator (e.g., creep, fatigue, stress relaxation). In some embodiments, the resonant frequency of the resonator may be tuned by laser trimming one or more resonator elements. In some embodiments, the resonant frequency of the resonator may be tuned to a target frequency using active temperature control of the resonator (e.g., a temperature controlled oven). Resonant frequency tuning based on active temperature control can eliminate resonant frequency drift due to changes in ambient temperature. Resonant frequency tuning with active temperature control can correct for resonant frequency variations due to device variations by driving the resonator to the target frequency by tuning the temperature control set point.

In some embodiments, the resonator and tuning element are designed to allow a sufficiently wide tuning range of the resonator resonant frequency to account for any variations encountered during manufacture and use. In some embodiments, the controller provides instructions to activate an on-chip or off-chip frequency reference (e.g., a quartz-based resonator or oscillator or other form of frequency reference) to provide a frequency reference signal. In some embodiments, the frequency reference signal is at a target resonant frequency of the resonator (independent of the resonant frequency of the resonator). In some embodiments, the frequency reference signal may be below or above the target resonant frequency. In some embodiments, the frequency synthesizer may use the frequency reference signal to generate the target resonant frequency based on the numerical multiplication factor. In some embodiments, the frequency multiplier may be less than 1 or greater than 1. In some embodiments, the controller provides instructions to apply the target resonant frequency to the resonator input. The controller instructs the tuning element to adjust the resonant frequency of the resonator (e.g., by changing a tuning capacitor, by adjusting a DC voltage bias). In one embodiment, with the input amplitude of the target resonant frequency fixed, the controller instructs the tuning element to sweep through the range of resonant frequencies achievable by the resonator (e.g., a series of capacitance values if the tuning element controls the resonant frequency with a variable capacitance), while capturing the response of the resonator via the output of the response sensing element. The controller instructs the tuning element to adjust the resonant frequency of the resonator to a value at which the response sensing element detects a maximum response.

In some embodiments, frequency tuning may also be achieved by comparing an external reference frequency (e.g., clock) or target resonant frequency to the resonator resonant frequency using a frequency difference detector (e.g., an analog or digital Phase Locked Loop (PLL) in conjunction with one or more dividers, multipliers, fractional-N architectures, phase detectors, and/or other typical PLL architectures or other frequency comparison systems (e.g., frequency counters)). In some embodiments, the external reference frequency is related to a target resonant frequency of the resonator (independent of the resonant frequency of the resonator) by a numerical multiplication factor. In some embodiments, the resonator may be configured with a loop gain >1 to form an oscillator, and the response signal from the oscillation of the resonator is used in the comparison of the frequency difference detector (e.g., to drive a frequency divider or fractional-N circuitry or other PLL circuit configuration). In some embodiments, the locking of the resonator resonance frequency by the tuning element to the external reference frequency (sweeping the resonance frequency) then allows the measurement of the required tuning parameters, which can then be applied by the tuning element to tune the resonator even after disconnecting the PLL and the external reference frequency.

in some embodiments, the controller performs any of the above resonator frequency tuning processes based on a set schedule. In some embodiments, the controller performs any of the resonator frequency tuning processes described above based on one or more of: resonator temperature, time elapsed since last tuning, amplitude of last tuning adjustment, etc. By performing the resonator frequency tuning process as needed, significant power savings can be achieved. The scheduling of the resonant frequency tuning allows correction of slowly drifting resonant frequencies and ensures long-term sensitivity of the resonator.

fig. 14 illustrates an exemplary schematic diagram of a system incorporating frequency referencing. The high stability reference oscillator 1401 output is fed to a frequency comparator and clipping circuit 1402. The output of the frequency comparator and clipping circuit 1402 is fed to a tunable oscillator 1403. The output of the tunable oscillator 1403 is fed to a resonator (not shown) that needs to be tuned. The output of the tunable oscillator 1403 is also fed back to the frequency comparator and clipping circuit 1402. Activation of the frequency reference and tuning process control is managed by the controller.

resonator resonant frequency tuning can be based on measurements of the resonant frequency using one of the methods described above, or based on stored information of the resonator for some source of resonant frequency variation. For example, temperature-resonant frequency information characterizing the change in resonant frequency of the resonator with temperature may be used to tune the resonant frequency. In some embodiments, the resonant frequency of the resonator may be tuned based on the measurements of the temperature associated with the resonator and the stored temperature-resonant frequency information. In another example, resonant frequency information specific to a given resonator (e.g., the resonant frequency of the given resonator (e.g., based on manufacturing variations)) may be used to tune the resonant frequency.

In some embodiments, the same circuitry used to receive data using an RF super regenerative receiver may be used to implement the RF transmit operation. In the case where the frequency is tuned to a frequency (e.g., "0" or "1") corresponding to data to be transmitted and the amplifier is set to a selected gain, a continuous RF carrier may be generated and transmitted. The data to be transmitted may be used to change the tuning frequency of the resonator while the resonator output is amplified and connected to the antenna.

In some embodiments, the frequency tuning capability of the resonator in the receiver additionally allows the resonator system (e.g., a MEMS-based resonator coupled to a feedback element) to operate as an FSK or other frequency modulation-based transmitter, thereby implementing the complete transceiver in one simple device. In some embodiments, MEMS-based systems operate as closed-loop oscillators (loop gain set above 1) in which FSK modulation is enabled via a tuning voltage applied across one or more electrodes of the MEMS resonator, such transmitters providing direct carrier generation at the RF frequency of interest, without the high power consumption complexity of previous PLL-based MEMS transmitters. In some embodiments, instead of an applied tuning voltage, the use of a variable capacitance connected to one or more ports of the resonator may be used to shift the frequency. Similarly, in some embodiments, the amplitude modulation may be affected by changing the gain of the feedback element. Additional embodiments may use a MEMS (or other resonator) based oscillator as a tunable reference for a standard fractional-N (and other configurations) PLL synthesizer to generate a modulated carrier for transmission. In some embodiments, power amplifier and switching circuitry may be included to produce the desired transmission power and shared antenna access.

Those skilled in the art will recognize that the resonators described in this disclosure may be selected from (but not limited to) one or more of the following: comb-drive resonators, piezo-coupled resonators, ring resonators, contour-mode ring resonators, lamb wave resonators, contour-mode resonators, goblet-disk resonators, goblet-ring resonators, Lame-mode resonators, strip resonators, bending beam resonators, film resonators, comb-drive bending-mode resonators, center-supported disk resonators, Surface Acoustic Wave (SAW) devices, Bulk Acoustic Wave (BAW) devices, thin Film Bulk Acoustic Resonator (FBAR) devices, transverse over-modulus bulk acoustic resonator (LOBAR) devices, piezo-actuated resonators, internal dielectric actuated resonators, internal transduction resonators with capacitive coupling formed from semiconductor junctions, and combinations of the foregoing. In some embodiments, the systems and methods described herein may be applied to resonator systems using any combination of inductors, capacitors, and resistors. In some embodiments, on-chip or off-chip resonator technology may be used, such as quartz or inductor-capacitor resonators. In some embodiments, the disclosed super-regenerative receiver systems and methods may be used in or with an oscillator without an RF wireless signal coupled to the oscillator.

The specific operating frequencies described in a given embodiment are exemplary. The frequency may be any value or range desired for the particular protocol used. Similarly, the Q factor may be any value or range desired for a particular resonator design. Similarly, the dimensions of the resonator may be selected based on any requirements (e.g., technical requirements, commercial requirements).

in some embodiments, the resonator may be fabricated using commercially available CMOS processes, CMOS compatible MEMS processes, non-CMOS compatible MEMS processes, or combinations thereof. In some embodiments, the resonator may be assembled using two or more substrates in combination (e.g., laterally, stacked) to form the resonator, where each substrate is fabricated using commercially available CMOS processes, CMOS compatible MEMS processes, non-CMOS compatible MEMS processes, or combinations thereof. In some embodiments, a resonator (e.g., a resonator fabricated from a 10um thick silicon substrate bonded to a standard thickness silicon substrate) can be fabricated by stacking, bonding, and patterning one or more substrates.

an exemplary process for fabricating a piezoelectric transduction based lamb wave MEMS resonator as described herein is illustrated in fig. 15 and 16. The fabrication process starts with a silicon substrate (fig. 15A) with an oxide (SiO2) layer (layer 1) and a metal layer (layer 2) deposited on top (fig. 15B). The metal layer (layer 2) is patterned using a first mask (e.g., using photoresist and photolithography) and etched (e.g., using plasma or wet etching) (fig. 15C). An aluminum nitride layer (layer 3) is deposited on the patterned substrate. The aluminum nitride layer (layer 3) was patterned using a second mask and etched (e.g., using Cl2/BCl3 plasma) (fig. 15D). A second metal layer (layer 4) is deposited on the patterned substrate (fig. 16A). The second metal layer (layer 4) is patterned using a third mask and etched (fig. 16B). The aluminum nitride layer (layer 3) and the oxide layer (layer 1) are patterned using a fourth mask and etched (e.g., using plasma or wet etching) (fig. 16C). The patterned structure was then etched using XeF2 gas and gas phase HF to create a suspended AlN plate (using layer 3) supported by a support beam (not shown), with optional electrodes on top (using patterned layer 4) and on the bottom (using patterned layer 2) (fig. 16D). Electrical contact to the layer 2 electrode or the layer 4 electrode on the AlN board may be established by extending one or more traces along one or more support beams for each electrode.

Hermetic sealing of the MEMS resonator may be necessary to reduce aging effects and prevent variation with environmental factors. This may be achieved via a hermetic package sealing or chip-level hermetic sealing process to the resonator. Chip scale processes may be suitable for large scale production due to their low cost and complexity. While the exact technique used depends on the foundry and MEMS/resonator processes, there are many such chip-scale processes.

In some embodiments, challenges in building a complete market ready product may include assembly, where MEMS dies may be wire bonded together with CMOS dies using conventional multi-chip wire bonding using wedge or ball bonds, and the dies side by side or stacked. Alternative methods for tighter integration and lower packaging cost may include flip chip or full wafer bonding, or even MEMS fabrication directly on top of CMOS.

In some embodiments, the design of higher level stack components is a significant part of the power consumption of the complete radio chipset. This includes low-level hardware controller circuitry, data processing and higher-level software stacks required for most protocols, and general-purpose microprocessor capabilities required for end-use applications. To this end, a low power design is required, which in some embodiments may include a sub-threshold circuit design, or an additional power-optimized IC die in the same package as the other components to provide a low power ARM core or the like. In doing so, price or power optimized CMOS nodes may be used for RF components, while more expensive but higher performance nodes may be used for microprocessors.

As used herein, in the specification and claims, "coupled" shall be understood to mean coupled at least one of capacitively, inductively, resistively (e.g., using a lead or trace electrical connection), or via a piezoelectric effect, unless explicitly stated to the contrary.

As used herein, unless explicitly indicated to the contrary, a "controller" in the specification and claims refers to a processing unit that is present anywhere in the stack of radio chipsets (including the physical layer).

While various embodiments have been described and illustrated herein, those of ordinary skill in the art will readily envision a variety of other means or structures for performing the functions or obtaining the results or one or more of the advantages described herein. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are exemplary and that the actual parameters, dimensions, materials, or configurations will depend upon the specific application or applications for which the teachings disclosed are used. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, equivalents to the specific embodiments described herein. It is, therefore, to be understood that the foregoing embodiments are presented by way of example only and that, within the scope of the appended claims and equivalents thereto, embodiments may be practiced otherwise than as specifically described and claimed. Embodiments of the present disclosure are directed to each individual feature, system, article, material, kit, or method described herein. In addition, any combination of two or more such features, systems, articles, materials, kits, or methods from different embodiments is included within the scope of the present disclosure if such features, systems, articles, materials, kits, or methods are not mutually inconsistent.

The above-described embodiments may be implemented in any of a variety of ways. For example, embodiments may be implemented using hardware, software, or a combination thereof. When implemented in software, the software code may be executed on one or more processing units, whether disposed in a single computer or distributed among multiple computers.

Also, a computer may have one or more input and output devices. These devices may additionally be used to present a user interface. Examples of output devices that may be used to provide a user interface include printers or display screens for visual presentation of output and speakers or other sound generating devices for audible presentation of output. Examples of input devices that may be used for the user interface include keyboards, and pointing devices, such as mice, touch pads, and digitizing tablets. As another example, a computer may receive input information through speech recognition or other audible format.

The computers may be interconnected IN any suitable form by one or more networks, including a local area network or a wide area network, such as an enterprise network, and an Intelligent Network (IN) or the Internet. These networks may be based on any suitable technology and may operate according to any suitable protocol and may include wireless networks, wired networks, or fiber optic networks.

A computer employed to implement at least a portion of the functionality described herein may include one or more memory units, one or more processing units (also referred to herein simply as "processors"), one or more communication interfaces, one or more display units, and one or more user input devices. The memory unit may include any computer-readable medium and may store computer instructions (also referred to herein as "processor-executable instructions") for implementing various functions described herein. A processing unit (e.g., any suitable controller (e.g., programmable controller, ASIC, FPGA), core (e.g., CPU, GPU, DSP, SoC), or any combination thereof) may be used to execute instructions. The communication interface(s) may be coupled to a wired or wireless network, bus, or other communication means, and thus may allow the computer to send and receive communications to and from components or other devices in the same device. For example, display unit(s) may be provided to allow a user to view various information related to execution of instructions. For example, user input device(s) may be provided to allow a user to manually adjust, make selections, enter data or various other information during execution of instructions, or interact with the processor in any of a variety of ways.

the various methods or processes outlined herein may be coded as software that is executable on one or more processors that employ any one of a variety of operating systems or platforms. Further, such software may be written using any of a number of suitable programming languages or programming or scripting tools, and may also be compiled as executable machine language code or intermediate code that is executed on a framework or virtual machine.

The concepts described herein may be implemented as a computer-readable medium (or multiple computer-readable media) (e.g., a computer memory, one or more floppy disks, compact disks, optical disks, magnetic tapes, flash memory, circuit constructions in field programmable gate arrays or other semiconductor devices, or other non-transitory or tangible computer storage media) encoded with one or more programs that, when executed on one or more processing units or computers, perform methods that implement the various embodiments described herein. The computer readable medium may be transportable, such that the one or more programs stored thereon can be loaded onto one or more different processing units or computers to implement the various aspects and embodiments described herein.

The terms "program" or "software" are used herein in a generic sense to refer to any type of computer code or set of computer-executable instructions that can be employed to program a processing unit or computer to implement various aspects of embodiments as described herein. Furthermore, according to one aspect, one or more computer programs that, when executed, perform methods or operations described herein without residing on a processing unit or computer, but may be distributed in a modular fashion amongst a number of different processing units or computers to implement various aspects or embodiments described herein.

Computer-executable instructions may be in many forms, such as program modules, executed by one or more computers or other devices. Generally, program modules include routines, programs, objects, components, or data structures that perform particular tasks or implement particular abstract data types. Typically, the functionality of the program modules may be combined or distributed as desired in various embodiments.

the data structures may be stored in any suitable form on a computer readable medium. For simplicity of illustration, the data structure may be shown with fields that are related by location in the data structure. Such relationships may also be implemented by allocating storage for fields that have places in a computer-readable medium that convey relationships between the fields. Any suitable mechanism may be used to establish a relationship between information in fields of a data structure, including through the use of pointers, tags, or other mechanisms that establish a relationship between data elements.

The concepts described herein may be implemented as one or more methods, examples of which have been provided. Unless otherwise limited herein, actions performed as part of the method may be ordered in any suitable manner. Accordingly, embodiments may be constructed which perform acts in an order different than illustrated, which may include performing some acts simultaneously, even though shown as sequential acts in exemplary embodiments.

The indefinite articles "a" and "an" as used in this specification and claims should be understood to mean "at least one" unless explicitly indicated to the contrary.

unless otherwise stated, references to "or" may be construed as logically non-exclusive or any item described using "or" may indicate a single, more than one, or all of the described items.

In the claims, as well as in the specification above, all transitional phrases such as "comprising," including, "" carrying, "" having, "" containing, "" involving, "" holding, "" consisting of … …, and the like, are to be construed as open-ended, i.e., to mean including but not limited to.

is incorporated by reference

All references, articles, publications, patents, patent publications and patent applications cited herein are incorporated by reference in their entirety for all purposes. However, the mention of any reference, article, publication, patent publication or patent application cited herein is not, and should not be taken as, an acknowledgment or any form of suggestion that it forms part of the common general knowledge in any country in the world or that it forms an admission that it forms part of the common general knowledge in any country in the world, or that it discloses something necessary.

Further embodiments of the invention

other subject matter contemplated by the present disclosure is set forth in the following numbered examples:

1. An RF receiver, comprising:

A resonator comprising two or more electrodes, wherein each of the two or more electrodes is coupled to at least one other of the two or more electrodes, and the two or more electrodes comprise at least one feedback electrode; and

A feedback element coupled to the at least one feedback electrode, wherein the feedback element has a gain that is controlled based at least in part on one or more feedback control signals and that is controlled to change from a first value to a second value through at least one intermediate value during a period of a single symbol.

2. the RF receiver of embodiment 1 wherein the feedback element comprises a controlled impedance element.

3. the RF receiver of any of embodiments 1-2 wherein the two or more electrodes include at least two feedback electrodes and the controlled impedance element is differentially coupled to the at least two feedback electrodes.

4. The RF receiver of any of embodiments 1-3 wherein at least one of the one or more feedback control signals controls at least one of the at least one feedback electrodes to be coupled to a dissipative element during at least a portion of a period of a single symbol.

5. The RF receiver of embodiment 1 wherein the two or more electrodes include at least two feedback electrodes, the feedback element includes a closed loop feedback element, and the closed loop feedback element is coupled to the at least two feedback electrodes.

6. The RF receiver of embodiment 5 wherein the resonator includes four or more electrodes including at least four feedback electrodes and the closed-loop feedback element is differentially coupled to the at least four feedback electrodes.

7. The RF receiver of embodiment 5 wherein at least one of the one or more feedback control signals controls at least one of the at least two feedback electrodes to be coupled to a dissipative element during at least a portion of a period of a single symbol.

8. the RF receiver of embodiment 5 wherein at least one of the one or more feedback control signals controls at least two of the at least two feedback electrodes to be coupled to each other via a dissipative element to each other during at least a portion of a period of a single symbol.

9. the RF receiver of any of embodiments 1-8, further comprising:

A tuning element coupled to at least one tuning electrode, wherein the two or more electrodes include the at least one tuning electrode, the tuning element is controlled by one or more frequency control signals, and a resonant frequency of the resonator is controlled by the tuning element.

10. the RF receiver of embodiment 9 wherein the tuning element comprises one or more capacitors, at least one of the one or more frequency control signals controls an output capacitance of the tuning element, and the resonant frequency is based at least in part on the output capacitance of the tuning element.

11. The RF receiver of embodiment 9 wherein the tuning element comprises a voltage source, at least one of the one or more frequency control signals controls an output voltage of the tuning element, and the resonant frequency is based at least in part on the output voltage of the tuning element.

12. The RF receiver of any of embodiments 9-11 wherein at least one of the one or more frequency control signals is based at least in part on a temperature associated with the resonator.

13. The RF receiver of any of embodiments 9-12 wherein at least one of the at least one feedback electrode and at least one of the at least one tuning electrode are coupled to a first electrode of the two or more electrodes.

14. The RF receiver of any of embodiments 9-13, further comprising:

A response sensing element coupled to at least one response sensing electrode, wherein the two or more electrodes include the at least one response sensing electrode, an output of the response sensing element is based at least in part on a response of the resonator, and at least one of the frequency control signals is based at least in part on the output of the response sensing element.

15. the RF receiver of embodiment 14 wherein the response of the resonator is an amplitude of a voltage on at least one of the at least one responsive sense electrode and the resonant frequency is based at least in part on the output of the responsive sense element.

16. The RF receiver of one of embodiments 1-15 wherein the gain is a loop gain, the first value corresponds to a loop gain of zero or less, the intermediate value corresponds to a loop gain between zero and one, and the second value corresponds to a loop gain of one or more.

17. The RF receiver of one of embodiments 1-15 wherein the gain is a loop gain and the first value corresponds to a loop gain of zero or less.

18. The RF receiver of one of embodiments 1-15 wherein the gain is a loop gain, the intermediate value corresponding to a loop gain of less than one.

19. The RF receiver of one of embodiments 1-15 wherein at least one of the one or more feedback control signals controls the gain to change to a negative value during at least a portion of a period of a single symbol.

20. the RF receiver of one of embodiments 1-15 wherein the first value of the gain corresponds to a feedback element having a negative gain.

21. The RF receiver of one of embodiments 1-15 wherein the intermediate value is controllable and the intermediate value is selectable from two or more target values.

22. The RF receiver of one of embodiments 1-21 wherein the resonator types include at least one of the following MEMS categories: surface micromachined micromechanical structures, bulk micromachined micromechanical structures, piezoelectrically actuatable micromechanical structures, and capacitively actuatable micromechanical structures.

23. The RF receiver of one of embodiments 1-22 wherein the resonator has a first Q factor with a gain equal to the first value, the resonator has a second Q factor with a gain equal to the intermediate value, and the first Q factor is different from the second Q factor.

24. The RF receiver of one of embodiments 1-23, further comprising:

A response sensing element coupled to at least one response sensing electrode, wherein the two or more electrodes include the at least one response sensing electrode, and an output of the response sensing element is based at least in part on a response of the resonator.

25. the RF receiver of embodiment 24 wherein the resonator has a first Q factor with a gain equal to the first value, the resonator has a second Q factor with a gain equal to the intermediate value, and the first Q factor is different from the second Q factor.

26. the RF receiver of one of embodiments 24-25 wherein the response of the resonator is an amplitude of a voltage on at least one of the at least one responsive sense electrode.

27. The RF receiver of one of embodiments 24-25 wherein the response of the resonator is the magnitude of the current sensed using at least one of the at least one responsive sense electrodes.

28. The RF receiver of one of embodiments 24-27 wherein at least one of the one or more feedback control signals is based at least in part on an output responsive to a sensing element.

29. The RF receiver of one of embodiments 24-28 wherein at least one of the first value, the second value, or the intermediate value is based at least in part on an output of the responsive sensing element.

30. The RF receiver of one of embodiments 4, 7 and 8 wherein the dissipative element comprises a resistive element.